Liquid jet cutting devices are in common use for cutting a wide variety of materials. Such a device usually consists of a source of high pressure fluid such as a hydraulic intensifier, a conduit system and an orifice. The orifice is often a jewel such as synthetic sapphire pierced by a hole which creates the sharp edged orifice. Mountings for the jewel are often quite complex as they must withstand both high pressure and rapidly changing pressure.
A major design problem with waterjet cutting apparatus is the presence of turbulence upstream of the orifice. If turbulence is present upstream of the orifice, the result is turbulence in the cutting jet which increases the size of the kerf, reduces the cutting ability, and may also result in undesirable wetting of the substance being cut. The most successful means of preventing turbulence to data is the addition of a collimating chamber upstream of the orifice. This type of device is described in U.S. Pat. No. 3,997,111. A disadvantage of such a chamber is the additional length and weight of the cutting assembly. Accordingly, a demand exists for a lightweight simple means of collimating fluid flow upstream of an orifice.